When a car can either travel at 250km/h, reach 100 kph within 5 secs, or finish Nürburgring Nordschleife within 8 mins, we say it is fast. These are measurements quantifying the quickness because “being fast” is rather a statement of feeling. In fact, this feeling is so objective and dependent on the situation that a single index cannot cover it perfectly. Multiple aspects have to be considered when reviewing the complete performance of a car.
Common figures seen in the specification tables are 0–100km/h acceleration time, top speed, and sometimes 400m acceleration time. These are measurements of driving without changing direction. In the real world, however, roads could not be infinitely straight, and the handling at corners could be another crucial factor for the speed. The slalom test is designed for cornering performance, and the lap time in a certain circuit measures both acceleration and cornering. The lap time at Nürburgring Nordschleife is widely regarded as the ultimate performance index in the world.
A car cannot be perfect. Usually one is good in some aspects but short in others. For example, Bugatti is known for producing cars with a crazy top speed of over 400km/h, but neither Veyron nor Chiron performed well on the track. This kind of drag race machine focuses on straight-line acceleration instead of lap time. Even in terms of lap time, different cars are built for different environments. Porsche dominates the rather curvy Nürburgring, but Ferrari would be better in a more spacious high-speed track.
Normally, an agile car cannot be too heavy; otherwise, it would be hard to go around curves. Mercedes-AMG GT 63S has proven the idea wrong as a big heavy sedan weighing over 2 tons. Although based on the E-Class platform, the GT 4-door gets the four-wheel steering and the rear differential from AMG GT. Its record at Nürburgring is 7 mins 25 secs, even faster than BMW M5 Competition.
Nissan GTR (R35) is another example that a heavy car can fly. Kazutoshi Mizuno, the father of GTR, believes in perfect weight balance rather than pure lightweight. Developed under his philosophy, GTR weighs 1.8 tons but accelerates almost as fast as supercars thanks to the AWD and the special rear-gearbox layout.
BMW G29 Z4 M40i is on the opposite side of GT63s and GTR. With merely 340PS as an EU version, its Nürburgring lap time is 7 mins 55 secs, leaving some horsepower monsters behind. Similarly, Lotus builds hardcore lightweight sports cars purely for handling rather than extreme top speed.
Nowadays, even SUVs get a superpower. Both equipped with the same 4.0 V8, Lamborghini Urus and Porsche Cayenne turbo can almost take off in straight-line acceleration just like those supercars. When swirling over corners, however, their heaviness and high center of mass will be exposed.
How about the fastest vehicles — F1 race cars? In fact, cars from different constructors still perform differently, and none are perfect. Take a look at the best two constructors of the 2019 F1 Championship — Mercedes and Ferrari. Their cars look rather similar from the outside, but the aerodynamic design differs. Mercedes’ car generates more downforce and thus is faster at corners, while Ferrari’s has less downforce but runs better at straight acceleration. Though Mercedes has been dominating the F1 since the V6-hybrid era, on high-speed circuits like Canadian Gran Prix, Ferrari has an edge on it. The qualifying record of Sebastian Vettel and Lewis Hamilton in the 2019 Canadian Gran Prix shows the exact difference: Vettel was faster on the straight portion, and Hamilton turned faster at corners. Vettel took the pole position, but the time of them was close.
What exactly affects the performance of a car? First, the powertrain matters for both acceleration and cornering but not decisively. Engines that respond faster help gain speed, and so do gearboxes with more responsive shifting logic. Second, a lighter weight is more maneuverable, especially on twisty roads, but some technologies do counter the effect of a higher weight.
Third, the overall structure design determines the character of a car. This also affects aerodynamics. We do not expect Lamborghini Urus to act in the same way as Huracan even though they have similar power output. Last, traction and tire grip is even crucial at the time of driving. Good traction helps speed up the vehicle efficiently, and the tire grip is a key factor in the traction. One cannot even drive safely with a worn-out tire set.
In conclusion, a powerful car does not necessarily go fast on curvy roads; an agile car does not necessarily accelerate like a rocket; a big heavy car can still be good at handling and acceleration. Moreover, people consider more aspects than just performance and speed when choosing a car. Simply pursuing high performance comes with trade-offs and costs. A powerful engine may be less durable, and a gearbox with an immediate kick-down response tends to wear the components faster.
